Radius and tangent dresser for abrasive wheels



Sept. 20, 1966 P. BUNGE 3,273,554

RADIUS AND TANGENT DRESSER FOR ABRASIVE WHEELS Filed Nov. 8, 1963 5 Sheets-Sheet 1 FIG-l INVENTOR.

LOTHAR F. BUNGE ATTORNEY L. P. BUNGE Sept. 20, 1966 RADIUS AND TANGENT DRESSER FOR ABRASIVE WHEELS 3 Sheets-Sheet 2 Filed NOV. 8, 1963 NOE INVENTOR.

LOTHAR P. BUNGE ATTORNEY L. P. BUNGE Sept. 20, 1966 RADIUS AND TANGENT DRESSER FOR ABRASIVE WHEELS 5 Sheets-Sheet 3 Filed NOV. 8, 1963 'UELPIT INVENTOR. LOTHAR P. BUNGE.

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ATTO RN EY United States Patent 3,273,554 RADIUS AND TANGENT DRESSER FOR ABRASIVE WHEELS Lothar P. Bunge, 3312 Eleven Mile Road, Warren, Mich. Filed Nov. 8, 1963, Ser. No. 322,311 4 Claims. (Cl. 12511) This invention relates to a dresser for abrasive wheels and more particularly has reference to a machine for forming contoured cutting surfaces on the face of surface grinding wheels and the like.

Surface grinding apparatus normally includes a cylindrical grinding wheel mounted on a horizontal rotatable spindle disposed above a planar reciprocating or rotating table or chuck. Surface grinding frequently requires that the face of the grinding wheel be of a specific non-planar shape so as to permit contoured grinding of the workpiece. The contoured grinding wheel surface required is ordinarily a combination of tangents and/ or radii, either concave or convex.

Grinding wheel dressers presently in use include an arm adapted to hold the diamond cutting tool at one end and rotatably supported at the other end in a circular ball bearing mounting. The arm is adapted to rotate about the axis of the bearing which is parallel to the axis of the arm. The entire assembly is placed upon the machine table or chuck when in use. The distance between the tip of the diamond and the axis of the bearing determines the size of the radius cut into the grinding wheel. To provide tangential movement of the cutting tool, the arm is adapted to move transversely to its own axis and to the axis of the cutting tool along a slide mounted between the arm and the bearing races.

The principal problem encountered in precision tangent and radius dressing of abrasive wheels is the elimination of vibration or lateral movement in the cutting tool. Since the bearing provides the principal support for the arm and slide, the greater the distance between the cutting tool and bearing, and between the slide and bearing, the greater will be the likelihood of developing vibration or lateral movement in the cutting tool.

It is therefore the primary object of the present invention to provide a dresser for abrasive wheels wherein the respective distances between the cutting tool and the bearing, and between the slide and the bearing, are substantially reduced so as to lessen the possibility of unwanted vibration or lateral movement in the cutting tool.

In a preferred embodiment of the invention which will be subsequently described in detail, the slide is mounted within the circular ball bearing assembly and attached to the inner race. This eliminates the displacement between the slide and the bearing and consquently substantially reduces the presence of vibrations during the tangential movement of the slide. The entire assembly of bearing, arm and slide is supported on a surrounding frame structure, which is mounted on the spindle of the grinding wheel.

An important advantage of this structure is that it permits substantial movement in all directions of the cutting tool. Conventional dressing machines are severely limited in the length of horizontal travel of the tool; this is due to the vibrations that develop in the cutting tool when the arm and slide movements are substantially removed from the bearing. To increase the length of horizontal travel of the tool, the displacement of the movements from the bearing must necessarily also be increased, resulting in a greater likelihood of undersirable vibration and lateral movement. In the present structure, the length of travel is limited only by the dimensions of the bearing. Since the slide movement is completely within the bearing, no vibration will be created in the cutting 3,273,554 Patented Sept. 20, 1966 tool. As a result, the tool is movable horizontally to any point in the grinding wheel, including the grinding wheel axis.

As a result of this construction, the dresser may be very light in weight yet extremely resistant to the creation of undesirable vibrations.

Another advantage of the present structure is its adaptability to be sealed against dust and other foreign particles. By incorporating the slide mechanism directly within the bearing races, the bearing and the slide may be both sealed by means of single covers mounted on. the opposite sides of the bearing races.

A further advantage of the present invention is the ease of reworking the slide assembly parts after wear. This may be accomplished simply by removing the slide from the bearing, grinding the planar surfaces on one side of the slide, and bolting the assembly back in position on the bearing races.

A further advantage of the present device is that it may remain in position on the grinding machine during grinding operations, already aligned for subsequent dressings. Most conventional dressing machines are mounted on the grinding machine table or chuck. They must therefore be removed entirely before the grinding wheel may be used for actual grinding of a workpiece. Each time the dresser is to be used it must. be remounted on the chuck and realigned for dressing. With the present invention, the dresser remains on the machine, ready for immediate use, at all times.

Other objects and advantages of the present invention will be more readily apparent from the following detailed description of a preferred embodiment thereof. The description makes reference to the drawings in which:

FIGURE 1 is a perspective view of a dressing machine according to the present invention mounted on the spindle of a conventional surface grinding machine;

FIGURE 2 is a plan view of the assembly shown in FIGURE 1 with parts broken away;

FIGURE 3 is a sectional view taken along the lines 3-3 in FIGURE 2;

FIGURE 4 is a sectional view taken along the lines 44 in FIGURE 3;

FIGURE 5 is a detail view taken along the lines 5-5 in FIGURE 2; and

FIGURE 6 is a detail view showing the diamond cutting tip after the cutting of two radii and a tangent on the grinding wheel face.

Referring to the drawings in detail a conventional surface grinding machine is shown at 10, having a cylindrical abrasive wheel 12 mounted upon a horizontal spindle 14 which in turn is rotatably held in a collar 16. The collar is fixed to the grinding machine housing 18.

The dresser is mounted on the grinding machine by means of a yoke 20 which is bolted in place about the collar 16. The yoke is formed at one end of an elongated rectangular block 22 which extends parallel to the plane of the wheel 12. The end of the block opposite to the yoke includes a transverse slot 24 connection with a bore 25 in the block. A micrometer screw 26 extending along the interior of the bore 25 is adapted to be rotated; the head 27 of the screw is calibrated to indicate the position of a nut 28 disposed along the length of the screw. The nut 28 is connected by means of a bolt 30 to a slide member 32. The slide member has flanges 34 along each edge to which slide blocks 36 are attached by means of bolts 38. The flanges 34 and bolts 38 thus form a T-slot which fits slidingly along a corresponding T-way 40 and extending along the length of one face of the block 22. The slide member 32 is thus adapted to be translated horizontally with respect to the spindle 14 of the grinding machine by rotation of the micrometer screw 26.

The slide member 32 includes diagonal braces 42 and 44 at each end which support horizontal ways 46. The ways are braced in position by a horizontal cross-member 47. The slide member also includes a curved lower edge 48 adapted to permit the slide to move adjacent to the spindle without contacting the collar 16.

A horizontal annular member 50 is connected at two opposing edges to flat plates 52 which slidingly fit within the ways 46. Blocks 49 are disposed at opposite ends of the ways 46 so as to limit the horizontal motion of the plates 52 and annular member 50. A micrometer screw 54 is mounted in one of the ways 46 and extends along the length thereof to a point adjacent the plate 52. A nut 56 mounted on the screw 54 is fixed to the adjacent edge of the plate 52 so that rotation of the adjustment knob 58 on the end of the screw 54 produces a translational movement of the annular member 50 and the plates 52 along the ways 46.

The annular member 50 has a circular T-slot 60 in its upper face. Buttons 62 each having a lower T-nut 64 fitting within the T-slot 60 are adapted to slide along the length of the T-slot 60. A screw 66 extending through the button 62 and T-nut 64 may be rotated in order to lock the buttons in place at any point along the T-slot.

An inner structure generally indicated at 68 is disposed in a ball bearing mounting along the interior of the annular member 50. The inner portion of the annular member 50 comprises the outer race 70 of the bearing while an annular portion of the inner structure 68 comprises the inner race 72. As shown in FIGS. 3 and 4, an annular retaining member 74 is bolted to the lower surface of the annular member 50 such that the balls 76 are secured in bearing position between the inner race 72, the outer race 70, and the retaining member 74.

A tangent slide bar 78 extends horizontally from the first point on the upper surface of the inner race 72 to a second point diametrically opposite to the first point. The slide bar is secured in place by means of screws 80. Another screw 82 extends vertically through the slide bar and inner race 72 at one end of the slide bar; a plate 84 is threadingly disposed at the lower end of the screw 82 and is adapted, when the screw is tightened, to lock the retaining member 74 and inner race 72 together and thus prevent rotational movement of the slide bar and inner race.

As shown in FIGURE 5, at one end the slide bar 78 includes a curved plate 86 having calibrations 08 thereon which are adapted to be read in conjunction with adjacent calibrations 90 extending along the outer face of the annular member 50. The latter calibrations are scaled from to 360 degrees and are used to indicate the size of the angle through which the inner race is rotated.

An upper plate 92 is disposed on the upper surface of the slide bar 78. The upper plate is wider than the slide bar and is connected by screws 94 at its edges to the vertical projections 96 of a lower slide block 98. The lower portion of the slide block 98 is fixed to a horizontal elongated slide support 100 which extends transversely to the length of the slide bar 78 and bears at each end against a curved blade member 102 fixed to the inner race 72.

A pair of locking pins 104 extend through holes in the upper plate 92 and into an elongated slot 106 in the slide bar 78 which extends parallel to the length of the slide bar. The slot 106 is long enough to accommodate both pins 104. The slot is centered upon the slide bar such that when both pins are depressed into the slot, the upper plate 92 and the slide block 98 are positioned precisely at the center of the surrounding annular hearing. The locking pins 104 are notched along their length so as to be held in either open or closed position by springloaded transverse pins 108.

The slide support 100 includes flanges 110 upon which horizontal plates 112 are slidingly supported. The plates 112 are bolted to an arm support 114. The arm support 114 is bolted to a nut 116 which threadably engages a micrometer screw 118 extending horizontally below the slide support and fixed thereto. Rotation of the calibrated head 120 at the end of the screw 118 thus causes the arm support 114 to move horizontally at right angles to the extension of the slide bar 78.

The arm support 114 is fixed to a downwardly extending arm 122 which is adapted to hold a diamond cutting tool 124 in cutting position in front of the abrasive wheel 12. A screw 126 at the lower end of the arm 122 secures the cutting tool in position.

If desired, dust shields may be provided to eliminate dust and other foreign particles from the dresser parts. In FIGURE 3 a telescoping dust shield 123 of the type well known to the art is employed. A similar shield may be provided at each of the micrometer screws in the assembly. In addition, a sliding dust shield may be provided across the upper or lower surfaces of the inner and outer races and over the T-slot 60 in the annular member 50.

In operation, the diamond cutting tip 124 is placed in the arm 122 and locked in place by means of screw 126. A gauge may be employed to set the diamond in precise predetermined relationship with the arm so that the calibrations on the micrometer screw head 120 will indicate the exact distance between the vertical axis of the bearing and the cutting tip. The screw 118 therefore may be rotated so as to fix the radius of the cut to be made by the cutting tool. Gage blocks may also be employed, if desired, to fix this radial distance precisely.

The screws 26 and 54 are then actuated so as to move the entire bearing and slide assembly into the desired position with the cutting tip 124 abutting the grinding wheel 12 in readiness for the cutting operation.

The buttons 62 in the T-slot 60 in the annular member 50 are then locked in position with respect to the slide bar 78 so as to limit the extent of the rotation of the slide bar and inner race to the desired angle through which the radius is to be cut. This angle may be set according to the calibrations 90 on the annular member 50. With the grinding wheel actuated, the upper plate 92 on the slide bar 78 is grasped manually and the entire inner assembly connected to the inner race 72 rotated until the slide bar abuts the pre-set button 62. The result is that the cutting tip 124 is moved through the required are, cutting the desired contour into the abrasive wheel.

If desired, the machine may be reset for a second radius of a different size in the same manner as set forth above. These contours on the face of the grinding wheel may be either concave or convex, depending upon the position of the cutting tip with respect to the bearing axis. FIGURE 6 shows a grinding wheel on which two arcs of differing radii have been cut respectively at 130 and 132.

When a planar surface is to be cut on the face of the grinding wheel, the machine is adjusted so that the extension of the cutting tip is perpendicular to the plane of the desired cut. The machine may be brought into this position with the slide bar 78 abutting a pre-set button 62. The locking pin 104 which is adjacent to the desired direction of cut of the planar surface is then pulled up and the upper plate 92 pushed manually along the slide bar 73 in the desired direction. This causes the cutting tip 124 to move transversely to its extension and cut the desired planar surface. It can be seen that the positioning end cutting operation may be accomplished by two continuous movements after the button has been pre-set; first a rotational movement of the slide bar and inner race into abutment with the button, and then a linear sliding movement of the upper plate along the slide bar. If desired, the inner bearing could be secured against further rotation by locking the screw 82.

FIGURE 6 shows the cutting tip at 134 after the ocmpletion of a tangent cut 136.

In this manner, any combination of arcuate or planar surfaces may be cut into the grinding wheel at any point in the grinding Wheel material. After cutting, the upper plate may be slid along the slide bar 78 until the cutting tool is positioned to one side so as not to interfere with normal grinding operations. Alternatively, the screws 26 and 54 may be actuated to move the cutting tool to one side.

:If the lower surfaces of the blade members 102 of the slide support 100 become worn unevenly, these surfaces may be ground so as to again lie in a common plane; the upper plate 92 is then removed and the upper surfaces of the slide bar 78, and the vertical supports 9S, and the lower surface of the upper plate 92, reground so that the slide support 100 again bears evenly against the blade members 102.

Having thus described my invention, I claim:

1. A dresser for abrasive wheels, comprising:

a first member fixed with respect to said wheel;

a frame mounted on said first member and slidable therealong in a first direction;

an annular member slidable in said frame in a second direction perpendicular to said first direction, said annular member being the outer race of an annular bearing;

an annular inner race rotatable within said outer race;

a slide bar fixed to diametrically opposed points on said inner race;

a sliding structure adapted to slide along said slide bar;

an arm support on said sliding structure adapted to slide along said sliding structure in the direction perpendicular to the extension of said slide bar;

an arm fixed to said arm support;

and a cutting tip mounted in said arm and adapted to cut the face of said abrasive wheel.

2. The structure set forth in claim 1 wherein said outer race includes an annular slot extending along its surface, wherein at least one locking screw is slidingly disposed in said slot and is adapted, when locked, to provide resistance against lateral movement of the ends of said slide bar in the direction of said locking screw and thus resist rotational movement of said inner race in said direction.

3. The structure set forth in claim 1 wherein a pair of spaced apart parallel sliding locking pins extend through holes in said sliding structure into a slot in said slide bar, said slot having a length sufficient to simultaneously accommodate both of said locking pins and such that when both of said pins extend into said slot said sliding structure is centered upon the axis of said bearing.

4. A dresser for abrasive wheels, comprising:

a block fixed with respect to the spindle of said abrasive wheel;

a screw rotatable in said block;

a slide member removably fixed to a nut mounted on said screw, such that rotation of said screw moves said slide member in a first direction;

an annular member slidable along said slide member and forming an outer bearing race;

an annular inner race rotatable within said outer race;

a slide bar fixed to diametrically opposed points on said inner race;

a sliding structure adapted to slide along said slide bar;

a pair of spaced apart parallel locking pins slidingly extending through holes in said sliding structure, a slot in said slide bar, said slot having a length only sufiicient to simultaneously accommodate both of said locking pins and such that when both of said pins extend into said slot said sliding structure is centered upon the axis of said bearing;

an arm support on said sliding structure adapted to slide along said sliding structure in the direction perpendicular to the extension of said slide bar;

an arm fixed to said arm support;

and a cutting tip mounted in said arm and adapted to cut the face of said abrasive Wheel.

References Cited by the Examiner UNITED STATES PATENTS 1,182,362 5/1916 Fischer --l1.7 3,1 14,292 12/ 1963 Harris 144-1'34 FOREIGN PATENTS 929,430 7/ 1947 France.

HAROLD D. WHITEH EAD, Primary Examiner. 

1. A DRESSER FOR ABRASIVE WHEELS, COMPRISING: A FIRST MEMBER FIXED WITH RESPECT TO SAID WHEEL; A FRAME MOUNTED ON SAID FIRST MEMBER AND SLIDABLE THEREALONG IN A FIRST DIRECTION; AN ANNULAR MEMBER SLIDABLE IN SAID FRAME IN A SECOND DIRECTION PERPENDICULAR TO SAID FIRST DIRECTION, SAID ANNULAR MEMBER BEING THE OUTER RACE OF AN ANNULAR BEARING; AN ANNUALR INNER RACE ROTATABLE WITHIN SAID OUTER RACE; A SLIDE BAR FIXED TO DIAMETRICALLY OPPOSED POINTS ON SAID INNER RACE; A SLIDING STRUCTURE ADAPTED TO SLIDE ALONG SAID SLIDE BAR; AN ARM SUPPORT ON SAID SLIDING STRUCTURE ADAPTED TO SLIDE ALONG SAID SLIDING STURCTURE IN THE DIRECTION PERPENDICULAR TO THE EXTENSION OF SAID SLIDE BAR; AN ARM FIXED TO SAID ARM SUPPORT; AND A CUTTING TIP MOUNTED IN SAID ARM AND ADAPTED TO CUT THE FACE OF SAID ABRASIVE WHEEL. 